Population statistics and biological traits of Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae) affected by LC30 of thiamethoxam and pirimicarb

Although selective pesticides are recommended to use in integrated pest management (IPM) programmes, they could adversely affect biological agents. So, the aim of the current study was to investigate the LC₃₀ of pirimicarb and thiamethoxam on Hippodamia variegata. Two pesticides, pirimicarb and thiamethoxam, when applied at concentrations of 1522.8 and 251.3?mg (ai)/L, respectively, on the third instar larvae of the insect, produced 30% mortality. Also, results showed that neither pirimicarb nor thiamethoxam affect stage age distribution (c_x), fecundity (eggs/female) and adult development time. These two pesticides extended preadult duration significantly (p?<?0.0001, F?=?31.22, df?=?122). Also, survival rate (l_x) and age-specific reproductive value (v_x) decreased and some changes in age-specific life expectancy (e_x) happened. Generally, more adverse effects were found in the population treated by thiamethoxam. The results showed that pirimicarb and thiamethoxam have potential to harm the predatory ladybird in IPM programme, though in sublethal doses.     

cycle基因对噻嗪酮、噻虫嗪防治白背飞虱效果影响探索研究

白背飞虱Sogatella furcifera是我国重要的迁飞性水稻害虫,长期以来,其防治手段主要是化学防治。大量使用化学农药易导致环境污染及害虫抗药性增加等,因此需要探索高效的农药使用方法。本研究在1 d内不同时间点用0.27 g/L噻虫嗪、5 mL/L噻嗪酮对白背飞虱的致死率进行检测,结果发现,7∶00时噻虫嗪、噻嗪酮浸染72 h后的校正死亡率均最低,分别为54%、13.9%;16∶00时噻虫嗪、噻嗪酮浸染72 h后的校正死亡率均最高,分别为89.8%、44.9%。定量结果表明节律基因Sfcycle在白背飞虱雌虫或雄虫的中肠表达量最高,4龄和5龄若虫期在蜕皮前表达量比蜕皮后高,成虫期表达量相对稳定。RNAi研究结果发现Sfcycle能够影响白背飞虱P450基因SfCYP4DE1和SfCYP353D1v2的表达,用农药处理干涉后的白背飞虱死亡率都在7∶00、16∶00两个时间点都增高,且没有显著性差异,表明Sfcycle基因能够影响噻虫嗪、噻嗪酮对白背飞虱的防治效率。     

Sublethal neonicotinoid insecticide exposure reduces solitary bee reproductive success

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高效氯氟氰菊酯和噻虫嗪对红火蚁的室内毒力

[背景]高效氯氟氰菊酯和噻虫嗪是农业上常用的杀虫剂。[方法]在室内测定了0.25 g·L-1高效氯氟氰菊酯微囊悬浮剂和0.01%噻虫嗪胶饵对红火蚁的毒力。[结果]高效氯氟氰菊酯微囊悬浮剂对红火蚁有良好的触杀作用,触杀时间短,致死量大,具备毒力传导作用;噻虫嗪胶饵能通过虫体间交哺传导毒力,室内防治整巢红火蚁效果可达93.50%以上。[结论与意义]这2种药剂都具有有效防治红火蚁的潜力。     

噻虫嗪对昆虫病原线虫侵染韭菜迟眼蕈蚊能力的影响

【目的】为提高昆虫病原线虫对韭菜迟眼蕈蚊Bradysia odoriphaga Yang et Zhang幼虫的防治效果,将昆虫病原线虫与环境友好型化学杀虫剂混用是一条有效途径。【方法】测定了噻虫嗪与6个昆虫病原线虫品系混用对韭菜迟眼蕈蚊的作用效果,以及温度和土壤含水量对作用效果的影响,并进行了田间验证。【结果】田间推荐浓度噻虫嗪(100 mg·L~(-1))对6种供试线虫存活无显著影响。处理后3 d,低浓度噻虫嗪(15 mg·L~(-1))分别与6品系线虫混合后处理韭菜迟眼蕈蚊幼虫,其死亡率明显高于线虫和噻虫嗪单用处理。小卷蛾斯氏线虫SF-SN+噻虫嗪、印度异小杆线虫LN2+噻虫嗪和小卷蛾斯氏线虫All+噻虫嗪3种组合发挥杀虫作用的最适温度范围分别为20~25℃、25~30℃和25~30℃,显著高于其他温度;最适土壤含水量范围为10%~18%,也显著高于其他湿度。大田条件下,施用后7 d,单用噻虫嗪、线虫+噻虫嗪组合处理对韭菜迟眼蕈蚊的防治效果显著高于单线虫,且以芫菁夜蛾斯氏线虫SF-SN+噻虫嗪的防治效果最高,达到93%以上。【结论】芫菁夜蛾斯氏线虫SF-SN品系与噻虫嗪组合联合防治韭菜迟眼蕈蚊效果最好。     

Insecticide resistance in Bemisia tabaci from Cyprus

Abstract A comprehensive study on the Bemisia tabaci (biotype B) resistance to neonicotinoid insecticides imidacloprid, acetamiprid and thiamethoxam, and pyrethroid bifenthrin was conducted in Cyprus. The resistance level to eight field‐collected B. tabaci populations was investigated. The activities of enzymes involved in metabolic detoxification and the frequencies of pyrethroid and organophosphates target site resistance mutations were determined. Moderate to high levels of resistance were detected for imidacloprid (resistance factor [RF] 77–392) and thiamethoxam (RF 50–164) while low resistance levels were observed for acetamiprid (RF 7–12). Uniform responses by the Cypriot whiteflies could be observed against all neonicotinoid insecticides. No cross‐resistance between the neonicotinoids was detected as well as no association with the activity of the P450 microsomal oxidases. Only imidacloprid resistance correlated with carboxylesterase activity. Low to extremely high resistance was observed for insecticide bifenthrin (RF 49–1 243) which was associated with the frequency of the resistant allele in the sodium channel gene but not with the activity of the detoxification enzymes. Finally, the F331W mutation in the acetylcholinesterase enzyme ace1 gene was fixed in all B. tabaci populations from Cyprus.     

噻虫嗪和噻虫胺对鸟类的急性毒性与风险评估

[目的]明确噻虫嗪与噻虫胺2种新烟碱农药对鸟类的风险。[方法]采用经口灌胃法测定98%噻虫嗪或噻虫胺原药、30%噻虫嗪或20%噻虫胺悬浮剂、42%噻虫嗪或46%噻虫胺种子处理悬浮剂对日本鹌鹑的毒性等级。根据供试农药对鸟类的毒性数据,结合田间用药信息,开展了2种农药对鸟类的初级风险评估。[结果]98%噻虫嗪原药、30%噻虫嗪悬浮剂和42%噻虫嗪种子处理悬浮剂对日本鹌鹑的半致死剂量(7 d-LD₅₀)分别为1500、481和266 mg·kg^-1,毒性等级分别为低毒、中毒、中毒,悬浮剂和种子处理悬浮剂的毒性高于原药。98%噻虫胺原药、20%噻虫胺悬浮剂和46%噻虫胺种子处理悬浮剂对日本鹌鹑的7 d-LD₅₀分别为369、397和1569 mg·kg^-1,毒性等级分别为中毒、中毒和低毒,种子处理悬浮剂的毒性最低。噻虫嗪和噻虫胺的悬浮剂在水稻田间使用时,对鸟类急性、短期和长期暴露的风险商值均小于1,风险可接受;噻虫嗪和噻虫胺的种子处理悬浮剂在玉米田应用时,对鸟类急性、短期和长期暴露的风险商值均大于1,风险不可接受。[结论]噻虫嗪和噻虫胺的悬浮剂在田间应用时对鸟类相对安全,2种农药的种子处理悬浮剂可能对鸟类产生危害。在种子处理场景中,播种后尽可能覆土或覆膜,减少种子直接暴露被鸟类取食;在鸟类保护区域,应避免使用噻虫嗪和噻虫胺的种子处理悬浮剂,以减轻农药施用对鸟类的危害。     

西花蓟马对烯啶虫胺、噻虫胺和噻虫嗪的抗性风险和抗性稳定性

为明确使用新烟碱类杀虫剂烯啶虫胺、噻虫胺和噻虫嗪防治入侵害虫西花蓟马的抗性风险及抗性稳定性,本研究采用芸豆浸药法对西花蓟马敏感种群初羽化雌成虫进行连续筛选获得抗性种群,根据抗性现实遗传力计算公式分析西花蓟马对上述3种杀虫剂的抗性风险,预测其抗性发展速度,并测定抗性稳定性。结果表明: 经过30代抗性筛选,西花蓟马对烯啶虫胺、噻虫胺和噻虫嗪均达到高水平抗性(44.7、45.5和32.7倍)。西花蓟马对噻虫胺、烯啶虫胺和噻虫嗪的抗性发展速度依次降低,抗性现实遗传力分别为0.1503、0.1336和0.1258。对抗性种群在无选择压力下继续饲养10代,西花蓟马对烯啶虫胺、噻虫胺和噻虫嗪的抗性水平均出现一定程度的下降,但均未能恢复到敏感性水平。抗性选育后,西花蓟马若虫与成虫对杀虫剂的敏感性差异显著缩小,西花蓟马敏感种群及抗性种群若虫对上述3种杀虫剂的敏感性显著高于成虫。西花蓟马对烯啶虫胺、噻虫胺和噻虫嗪均存在高抗风险,噻虫嗪的抗性上升速度较慢且抗性稳定性最低。因此,在西花蓟马若虫期使用噻虫嗪有利于西花蓟马防治。     

Efficacy of pyrethroid and neonicotinoid insecticides for Melanotus communis (Gyll.) (Coleoptera: Elateridae) control in Florida sugarcane (Saccharum spp.)

Wireworms are important pests in newly planted sugarcane fields in Florida. Current management involves an integrated programme of cultural and chemical controls. Current chemical controls used are the organophosphates phorate and ethoprop. As federal regulations tighten the uses of organophosphates, effective chemicals from alternative classes of chemistry need to be found. The organophosphates were the only insecticides that effectively protected the emerging shoots from damage in our study. Phorate consistently reduced the number of wireworms. While the pyrethroids and neonicotinoids were able to protect the seed piece and non‐sprouted buds, they did not consistently protect shoots and tillers. Neither pyrethroids nor neonicotinoids caused wireworm mortality in excess of that which occurred naturally.     

45%烯肟菌胺·苯醚甲环唑·噻虫嗪种衣剂对麦田宽背金针虫和麦秆蝇的防治效果

采用田间试验评价的方法研究了45%烯肟菌胺·苯醚甲环唑·噻虫种衣剂对麦田宽背金针虫Selatosomus latus F.和麦秆蝇Meromyza saltatrix L.的防治效果。结果表明,该药剂对麦田宽背金针虫、麦秆蝇的防虫效果分别为71.43%-86.27%、55.35%-74.65%,以每10 kg种子80 g药剂处理防效最好;处理区小麦产量明显增加,增产率最高为15.87%。该三元复合种衣剂在防治小麦病虫害中具大面积应用的前景。